Autologous Bone Cranioplasty: A Retrospective Comparative Analysis of Frozen and Subcutaneous Bone Flap Storage Methods

Abstract

The use of autologous bone for cranioplasty offers superior cosmesis and cost-effectiveness compared with synthetic materials. The choice between 2 common autograft storage mechanisms (subcutaneous vs. frozen) remains controversial and dictated by surgeon preference. We compared surgical outcomes after autologous bone cranioplasty between patients with cryopreserved and subcutaneously stored autografts. Ten-year retrospective comparative analysis of patients undergoing cranioplasty with autologous bone stored subcutaneously or frozen at a tertiary academic medical center. Ninety-four patients were studied, with 34 (36.2%) bone flaps stored subcutaneously and 59 (62.8%) frozen. The 2 groups were similar in demographics, comorbidities, and craniectomy indication, with only body mass index and race differing statistically. The mean operation time was greater within the subcutaneous group (P < 0.001), which also had a greater number of ventriculoperitoneal shunt (VPS) placements (P= 0.02). There were no significant differences in complications, readmissions, unplanned reoperations, or length of stay between the 2 groups. VPS placement during cranioplasty increased length of stay (P < 0.001), and placement prior to cranioplasty increased both length of stay (P= 0.009) and incidence of hospital-acquired infection (P= 0.03). Subcutaneous and frozen storage of autologous bone result in similar surgical risk profiles. Cryopreservation may be preferred because of shorter operation time and avoidance of complications with the abdominal pocket, whereas the portability of subcutaneous storage remains favorable for patients undergoing cranioplasty at a different institution. VPS placement prior to cranioplasty should be avoided, if possible, due to the increased risk of hospital-acquired infection.